Picked up this 2006 today

[CR250_182]

I've been eyeballing it for about a week now and could not hold out any longer. It's had 2 owners, neither rode it much, but claimed to have done oil changes and such.

Stock tires,chain, sprockets, everything pretty much, if I had to guess I'd say no more than 10 hours. As you can tell I'm pretty pumped haha.

 

Just wondering since I'm coming from the Honda side, and not having much knowledge of the KX's what some of the common mods are that should be done. I'm going to set sag and ride it before I choose to have any revalving done, but other little things. I've heard timing air gap, and maybe lowering link, anything else to share?

 

[zz3gmc]

That bike came from NJ! Mt Holly Kawasaki is 10 minutes from me! What type of riding are you going to do with it?

 

[Greenwrench]

Nice bike !

[Hans Schmid]

Looks worn out, better send it too me... 

[CR250_182]

That bike came from NJ! Mt Holly Kawasaki is 10 minutes from me! What type of riding are you going to do with it?
 

Original owner was in the army and never rode it because he was deployed so it probably came from there to down here were I got it from the second owner who lived near an army base.
This bike will be a track only bike, no harescramble's for this bike.

Looks worn out, better send it too me... 

I'd hate to dump such a pile on you [emoji1]

[turbo dan]

Very nice bike.  Don't worry about the rear link.  Find a set of 22mm triple clamps and everything else will click with the chassis. 

Those forks work great with one more face shim on the mid valve comp stack and a stiffer base valve comp stack.  Add like five face shims to the base.  The shock is too soft in stock form as well.  Drop the 19mm clamp shim and put a 40x.25mm on top of the low speed stack.  I also changed all of the high speed shims to .3mm thickness. 

[CR250_182]

Very nice bike.  Don't worry about the rear link.  Find a set of 22mm triple clamps and everything else will click with the chassis. 
Those forks work great with one more face shim on the mid valve comp stack and a stiffer base valve comp stack.  Add like five face shims to the base.  The shock is too soft in stock form as well.  Drop the 19mm clamp shim and put a 40x.25mm on top of the low speed stack.  I also changed all of the high speed shims to .3mm thickness. 

Thanks for the tips. As for the triple clamps is there a certain year of oem parts or anything I should look for? Like a set of kx450f clamps or anything?

[turbo dan]

2002 KX125/250 are the ones you need.  Lots of them are listed as 99-02 but up until 01 they are 58.5mm instead of 59mm on the lower diameter.  Press your stem out of your existing clamps and press it into the new one and it all bolts up.

[CR250_182]

2002 KX125/250 are the ones you need.  Lots of them are listed as 99-02 but up until 01 they are 58.5mm instead of 59mm on the lower diameter.  Press your stem out of your existing clamps and press it into the new one and it all bolts up.

Awesome info, thanks. I'll be looking for a set.

[CR250_182]

Did a breakdown today to see what needs done. Looks like the only thing that really needs done is fork and shock seals. Also gonna get chains and sprockets to be on the safe side. A few other small things but nothing big right now, I just want to ride it for awhile to see what I want to change.
While I have everything apart I re-greased the linkage and swingarm bearings which looked brand new, scrubbed on the engine and frame a little, and cleaned the air filter. Should be ready to go soon.

[MatthewMCRepair]

Very nice, congrats.

[KDXGarage]

Very nice. Semi-common flaws reported are the air gap and te power valve spring.

 

DO look into different offset clamps. The forks definitely need help.

[turbo dan]

I've been running without that spring for many months now.  I had the power valve stick briefly on a few occasions until revs came back to idle but it has not happened in quite a while.  Super M at 32:1 keeps the power valve slick and clean so the spring is actually kind of redundant. 

Edited May 1, 2017 by turbo dan

[treedodgingfool]

The center powervalve if the governor rod spring is broken defaults to open. Very noticeable off the bottom, especially if you have intentions of riding single track or technical trails were that little extra bottom delivery helps, especially since the "R" doesn't have the grunt of the engine it replaced to begin with. I recommend checking that spring, depending upon how much you ride, at least twice a year. On my '07, that I spent a whole season competing in East coast Enduro's with, I went through two that year. Noticed it right away, felt like the bike needed a rebuild/soft on power. Otherwise, the steering head angle is steep on these and causes a knife/wash sensation, particularly on waltzing tight trail. Not as noticeable on rockier stuff, though. Do recommend the '02 clamps. There's quite a bit you could do to one of these to tailor fit the package to how you intend to ride it, just depends on if you're going to be riding track, two trackers/ATV width trail or single track.

[CR250_182]

Very nice. Semi-common flaws reported are the air gap and te power valve spring.
 
DO look into different offset clamps. The forks definitely need help.

I'm going to ride it a bit to see what I think, and keep my eyes open for some 02 triples in the meantime.
I'm a bit heavier than average, but not huge so I think a little later this year after I've ridden it I'm going to have the suspension re-valved, and get new springs if necessary.

The center powervalve if the governor rod spring is broken defaults to open. Very noticeable off the bottom, especially if you have intentions of riding single track or technical trails were that little extra bottom delivery helps, especially since the "R" doesn't have the grunt of the engine it replaced to begin with. I recommend checking that spring, depending upon how much you ride, at least twice a year. On my '07, that I spent a whole season competing in East coast Enduro's with, I went through two that year. Noticed it right away, felt like the bike needed a rebuild/soft on power. Otherwise, the steering head angle is steep on these and causes a knife/wash sensation, particularly on waltzing tight trail. Not as noticeable on rockier stuff, though. Do recommend the '02 clamps. There's quite a bit you could do to one of these to tailor fit the package to how you intend to ride it, just depends on if you're going to be riding track, two trackers/ATV width trail or single track.

I'll check the spring out and see what condition it's in. And I'll definitely be keeping an eye open for 02 triples.
This bike is definitely going to be my mx track only bike.

[turbo dan]

31 minutes ago, treedodgingfool said:

The center powervalve if the governor rod spring is broken defaults to open. Very noticeable off the bottom, especially if you have intentions of riding single track or technical trails were that little extra bottom delivery helps, especially since the "R" doesn't have the grunt of the engine it replaced to begin with. I recommend checking that spring, depending upon how much you ride, at least twice a year. On my '07, that I spent a whole season competing in East coast Enduro's with, I went through two that year. Noticed it right away, felt like the bike needed a rebuild/soft on power. Otherwise, the steering head angle is steep on these and causes a knife/wash sensation, particularly on waltzing tight trail. Not as noticeable on rockier stuff, though. Do recommend the '02 clamps. There's quite a bit you could do to one of these to tailor fit the package to how you intend to ride it, just depends on if you're going to be riding track, two trackers/ATV width trail or single track.

 

The spring only assists closing the power valve.  It will still function normally unless there is too much drag from carbon or varnish gumming up the valve, which can either cause it to stick fully open or just until revs drop back down to near idle.

The actuator in the case doesn't have as much leverage closing the valve as it does opening it, which is what the spring assists.  The actuator arm bolts directly to the main shaft of the power valve, so it is mechanically controlled at all times by the actuator in the case.  The spring just gives a little push in the right direction.  Seems to have been a bit of an afterthought on Kawasaki's behalf.

[treedodgingfool]

It defaults to open when clean upon reassembly too, at least on my '07 it always did (upon inspection). Besides, my powervalve at their service intervals aquire very little to any carbon deposits and operate fluidly as expected (110 leaded w/Maxima Super M, proper jetting, tight tolerances/regular service schedules, keep a motor clean). That spring is totally an afterthought in design, but a necessity for grunt, especially off-road. But you must excuse me since I have spent upwards of 70k miles on both '03 & '04 KX250's in various configurations for off-road racing since new, and though I do like the "R" models, especially the hit (very entertaining), it's not as good of a complete package in an off-road application as the "M" models, particularly the '04/M2, but that's besides the point.

As a dedicated track bike, the "R" with a few smart mods is a lot of fun. If you find yourself looking for more grunt, I can help aim you in the right direction with those mods having been there off-road already. Best spent money on a minty stock "R" bike would be the triple clamps, a suspension service or revalving/sprung to weight. I'd say a 52 rear sprocket to get the hit a little lower for corner exits. I'd also suggest running leaded race gas & jetting for it. If your regions pump gas has ethanol, ethanol & Japanese crank seals don't mix (dries the OEM ones up). Besides, once jetted for race fuel, the bike will run better, consistent, get better fuel economy because of the leaner jetting for the lighter fuel and not ping when hot/under a heavy load. If you do run pump w/ethanol, keep an eye on excessive smoke & tranny oil loss. KX250's have to have their cases split to replace crank seals.

[CR250_182]

As a dedicated track bike, the "R" with a few smart mods is a lot of fun. If you find yourself looking for more grunt, I can help aim you in the right direction with those mods having been there off-road already. Best spent money on a minty stock "R" bike would be the triple clamps, a suspension service or revalving/sprung to weight. I'd say a 52 rear sprocket to get the hit a little lower for corner exits. I'd also suggest running leaded race gas & jetting for it. If your regions pump gas has ethanol, ethanol & Japanese crank seals don't mix (dries the OEM ones up). Besides, once jetted for race fuel, the bike will run better, consistent, get better fuel economy because of the leaner jetting for the lighter fuel and not ping when hot/under a heavy load. If you do run pump w/ethanol, keep an eye on excessive smoke & tranny oil loss. KX250's have to have their cases split to replace crank seals.

I always do my best to get non-ethanol fuel. Thankfully there is a station near by that sells it. I have been considering running race gas, I just have done any research on it yet. Out of curiosity what brand do you run? I live in southern Missouri near some oval tracks and such so race fuel shouldn't be to hard to come by.
I have my forks apart right now waiting on seals to come in, and I'll be taking my shock to a shop. I think after I ride it awhile and get a feel for it I can weigh in on here about what I might be wanting to change/do.

[treedodgingfool]

I'm also near some tracks and have access to either Cam2/Sunoco 260GT 110 leaded (same fuel) or VP C12. We use Cam2/Sunoco 260GT. At $9.90 per gallon, it's a few dollars less then even what I could get the VP in a drum for and it's readily available from three different vendors in my area. Now my stock motored bikes would run fine on a 50/50 mix of pump/race, but since the nearest non-ethanol pump gas is around 2-3 hours away, its not very convenient! So we run straight race gas (& haven't had any crank seal issues since going full leaded race fuel). The other issue I have with pump is having gotten some questionable fuel in the past (from the same supplier too) and the bike runs like crap/erratic. I've never experienced that with race gas, it's always consistent. For the consistent performance & no detonation, elimating fuel related crank seal issues, cleaner components and improved fuel economy (about a 1/3 better then pump), I don't mind paying $10 a gallon. The other thing is, at least around here, while pump gas has fluctuated up & down (up to $4 a gallon for 93 when fuel was high), the race fuel has never changed. We've paid the same price for the past decade.

[turbo dan]

13 hours ago, treedodgingfool said:

It defaults to open when clean upon reassembly too, at least on my '07 it always did (upon inspection). Besides, my powervalve at their service intervals aquire very little to any carbon deposits and operate fluidly as expected (110 leaded w/Maxima Super M, proper jetting, tight tolerances/regular service schedules, keep a motor clean). That spring is totally an afterthought in design, but a necessity for grunt, especially off-road.

I wonder if it is the leaded fuel causing additional build-up.  Like I said, I have been running without the spring probably since I got the bike.  The first time I went in for maintenance it was broken and its been broken ever since.  I have experienced temporary valve sticking on two occasions.  Definitely not a significant issue for me.

The power valve linkage does not rely on the spring in any way to control the valve.  The spring just helps assist in closing the valve as the actuator doesn't have as much leverage in that direction as it does when opening.

13 hours ago, treedodgingfool said:

But you must excuse me since I have spent upwards of 70k miles on both '03 & '04 KX250's in various configurations for off-road racing since new, and though I do like the "R" models, especially the hit (very entertaining), it's not as good of a complete package in an off-road application as the "M" models, particularly the '04/M2, but that's besides the point.

As a dedicated track bike, the "R" with a few smart mods is a lot of fun. If you find yourself looking for more grunt, I can help aim you in the right direction with those mods having been there off-road already. Best spent money on a minty stock "R" bike would be the triple clamps, a suspension service or revalving/sprung to weight. I'd say a 52 rear sprocket to get the hit a little lower for corner exits. I'd also suggest running leaded race gas & jetting for it. If your regions pump gas has ethanol, ethanol & Japanese crank seals don't mix (dries the OEM ones up). Besides, once jetted for race fuel, the bike will run better, consistent, get better fuel economy because of the leaner jetting for the lighter fuel and not ping when hot/under a heavy load. If you do run pump w/ethanol, keep an eye on excessive smoke & tranny oil loss. KX250's have to have their cases split to replace crank seals.

I'm right there with you.  I was on an M series KX from 2002-2016.  They were definitely refined and dialed in at that point after an entire decade of development on that engine.  The 05-07 is a first generation machine and this shows in some areas.  I think a different jet needle might help alleviate some of that detonation too, though it rarely occurs on the track.

I've definitely had a different experience with ethanol blended fuel as well.  I've never run anything but E10 and I've never had a crank seal fail.  I only replace them if I'm rebuilding a bottom end, at which point you inevitably destroy the old ones pressing the main bearings out.  The rubber is still in fine condition though.